I will be officially divorced this Monday 12/29. It has been a 4 year ordeal for me. Just two months ago, my ex finally admitted to me she knew she had problems with the ideal of aging. I can understand this to a degree because she was a very attractive Woman and I've known her since she was 16. This is not a bias opinion on my part. I've had male friends tell me my W was hot. Of course, the partying and high anxiety and stress have taken their toll on her over the past few years. She looks noticeably older and she cried to me recently that her Father told her she was showing signs of age. She was devastated at her own Father telling her that. For the first time in her life, the things that came easy to her because of her looks, no longer apply. She has to look deeper inside herself for the first time to define herself. I've always known she had inner substance, but she didn't.
Reconciliation came to late for us. By the time she "snapped" out of it, I was no longer interested. This is going to be a bigger test for you than it is her. You may not want her back even if she does snap out of it. I know you can't conceive of that now, but trust me, that possibility exist the longer she stays in this behavior pattern. It's going to test your patience, perseverance, and sanity.
You shouldn't be asking how long it's going to take her to snap out of it, that comes in varying degrees depending on the person. What you need to concentrate on is how long your willing to wait to have her back and what you plan to do for yourself in the interim. Think of it as a long prison term. It's going to kill you to sit there in your cell counting the days until you get out. Make the best of this time for yourself now. Keep occupied and the time it takes won't be an issue for you.
"It is curious that physical courage should be so common in the world and moral courage so rare." -Mark Twain